MSDS Terms and Definitions

Identification:

Chemical Name

A group of single elements or compounds with a common name. Example; acetone, methylethyl ketone (MEK), and methyl isobutyl ketone (MIBK) are of the “Ketone” family; acrolein, furfural, and acetaldehyde are of the “aldehyde” family.

C.A.S. Number

Chemical Abstracts Service. A Columbus, Ohio organization which indexes information published in “Chemical Abstracts” by the American Chemical Society, and provides index guides by which information about particularsubstances may be located in the “Abstracts” when needed. “C.A.S. Numbers” identify specific chemicals.

Flammable and Combustible Liquids

Combustible liquid means any liquid having a flashpoint at or above 100oF (37.8oC). Combustible liquids are divided into two classes:

Class II liquids shall include those with flashpoints at or above 100oF (37.8oC) and below 140oF (60oC), except any mixture having components with flashpoints of 200oF (93.3oC) or higher, the volume of which make up 99 percent or more of the total volume of the mixture.

Class III liquids shall include those with flashpoints at or above 140oF (60oC). Class III liquids are subdivided into two subclasses:

Class IIIA liquids shall include those with flashpoints at or above 140oF (60oC) and below 200oF (93.3oC), except any mixture having components with flashpoints of 200oF (93.3oC), or higher, the total volume of which make up 99 percent or more of the total volume of the mixture.

Class IIIB liquids shall include those with flashpoints at or above 200oF (93.3oC). This section does not cover Class IIIB liquids. Where the term “Class III liquids” is used in this section, it shall mean only Class IIIA liquids.

When a combustible liquid is heated for use to within 30oF (16.7oC) of its flashpoint, it should be handled in accordance with the requirements for the next lower class of liquids.

Flammable liquid means any liquid having a flashpoint below 100oF (37.8oC), except any mixture having components with flashpoints of 100oF (37.8oC) or higher, the total of which make up 99 percent or more of the total volume of the mixture. Flammable liquids shall be known as Class I liquids. Class I liquids are divided into three classes as follows:

Class IA shall include liquids having flashpoints below 73oF (22.8oC) and having a boiling point below 100oF (37.8oC).

Class IB shall include liquids having flashpoints below 73oF (22.8oC) and having a boiling point at or above 100oF (37.8oC).

Class IC shall include liquids having flashpoints at or above 73oF (22.8oC) and below 100oF (37.8oC).

FLASH POINT — the lowest temperature at which a flammable liquid will give off enough vapors to form an ignitable mixture with the air above the surface of the liquid or within its container.

LOWER FLAMMABLE LIMIT — the percentage of vapor in the air below which a fire can’t occur because there isn’t enough fuel: the mixture is said to be too lean.

UPPER FLAMMABLE LIMIT — the percentage of vapor in the air above which there isn’t enough air for a fire: the mixture is said to be too rich.

VAPOR DENSITY — the weight of a flammable vapor compared to air. (Air = 1). Vapors with a high density are more dangerous and require better ventilation because thay tend to flow along the floor and collect in low spots.

PEL — the Permissible Exposure Limit of the vapor according to OSHA standards, expressed in parts of vapor per million parts of contaminated air. The PEL is listed because many of these substances present inhalation as well as fire hazards.

Reactivity

A description of the tendency of a substance to undergo chemical
reaction (usually with the release of energy). Undesirable effects such as
pressure buildup; temperature increase; formation of noxiuos, toxic, or
corrosive by-products; may occur because of the reactivity of a substance by
heating, burning, direct contact with other materials, or other coinditions of
use or storage. A solid waste which exhibits a “characteristic of
reactivity,” as defined by RCRA, may be regukated (EPA) as a hazardous waste.

Fire, Explosion & Reactivity:

Flash Point

The lowest temperature at which the material will flash or ignite when exposed to flame. Stated another way, it is the lowest temperature at which a liquid will produce sufficient vapor to burn. The flash points may vary for the same material depending on the method used, so the test method is indicated when the flash point is given. There are four accepted methods of testing flash point. The Tag Closed Cup (TCC or CC) is normally the preferred method. However, the Tag Open Cup (TOC),
Cleveland Open Cup (COC) and Pensky-Martens (PM) methods are also widely used to test flash point.

D.O.T

U.S. Department of Transportation. Regulates transportation of chemicals and other substances for the protection of the public; law enforcement, and emergency response personnel, particularly when transportation incidents occur involoving hazardous materials. Detailed DOT classification lists specify appropriate warning labels-such as Oxiding Agent or Flammable Liquid-which must be used for various substances during transport.

Stability

An expression of the ability of a material to remain unchanged.
For MSDS purposes, a material is stable if it remains in the same form under
expected and reasonable conditions of storage or use. Examples of conditions
which may cause instability (dangerous change) are: temperatures above 150 F
shock from dropping, combination with another chemical.

NFPA Classification

National Fire Protection Assn. An international volutary membership organization to promote/improve fire protection and provention, and establish safeguards against loss of life and property by fire. Best known on the industrial scene for the National Fire Codes- 16 volumes of codes, standards, recommended practices, and manuals developed and updated by NFPA technical committees. Among these is NFPA 704M, the code for showing hazards of materials using the familiar diamond-shaped label or placard with appropriate numbers or symbols. The brief expalnation below illustrates the NFPA principle of using scales of 0 to 4 (low to high) to classify material hazards.

Hazardous Combustible Decomposition Products

A term used by the National Fire Protection Assn. DOT, and others to classify certain liquids that will not burn, on the basis of flash points. In the hazard communication rules, a combustible liquid has a flash point at or above 100 F (37.8 C), BUT BELOW 200 F. Also, see combustible liquid in 1910.1200(C).

Hazardous Polymerization Products

A chemical reation in which one or more small compounds. A
hazardous poolymerization is such a reation which takes place at rate which
releases large amounts of enery (usually heat). If hazardous polymerization
can ooccur with a given material, the MSDS usually will list conditions which
could start the reaction; and since the material usually contains a
polymerization inhibitor, the expected time period before the inhibitor is
used up should be stated.

Physical Data:

Boiling Point

The temperature ar which a liquid changes to a vapor state, at given pressure; usually expressed on degrees Fahrenheit at sea level pressure (760 mmHg, or one atmosphere). For mixtures, the initial boiling point or the boiling range may be given. Flammable materials with low boiling points
generally present extreme fire hazards. Some approxiate boiling points:

Specific Gravity

The weight of the material compared to the weight of an
equal volume of water; an expression of the density (or heaviness) of the
material. Example; if a volume of a material weighs eight pounds, and equal
volume of water weights ten pounds, the material is said to have a specific
gravity of 0.8

8lbs material/10lbs water = 0.8 specific gravity

Insoluble materials with specific gravity of less than 1.0 will float in (or
on) water. Most (butnot all) flammable liquids have specific gravities less
than 1.0 and, if not soluble, will float on water, an important consideration
for fire suppression and spill clean-up.

Melting Point

The temperature at which a solid substance changes to a liquid
state. For mixtures, the melting range may be given.

Vapor Pressure

The pressure exerted by the vaporization of a liquid in a
closed container. When vapor pressure tests are proformed on products the
test temperature is usually 68-100 F, and the vapor pressure is expressed as
pounds per square inch. Vapor pressures reported on MSDS are in millmeters of
mercury at 68 F (20 C), unless stated otherwise. Three facts are important to
remember:

Vapor pressure of a substance at 100 F will always be higher than the vapor
pressure of the substance at 68 F (20 C).

Vapor pressures reported on MSDS in mmHg are usually very low pressures; 760
mmHg is equivalent to 14.7 pounds per square inch.

The lower the boiling point of a substance, the higher its vapor pressure.

Vapor Density

The weight of vapor or gas compared to the weight of an equal
volume of air; an expression of the density of the vapor or gas. Materials
lighter than air have vapor densities less than 1.0. Materials heavier than
air (examples: carbon dioxide, propane, hydrogen sulfide, ethane, butane,
chlorine, sulfur dioxide) have vapor densities greater than 1.0. All vapors
and gases will mix with air, but the lighter materials will tend to rise.
Heavier vapors and gases are likely to concentrate in low places (along or
under floors, in sumps, sewers and manholes, in trenches and ditches) where
they may create fire or health hazards.